Limited power output

[m0rph]

I can't find any information so far, so I started this new thread..

My car (2011 - 2.5) is back from the service center, after a complete rebuild costing over € 60000:

• New motor
• New PEM (reman)
• Other battery (a loaner 2.0 battery with CAC 141 - installed while waiting for the 3.0 battery).
• New PEM/Motor cooling fan

Unfortunately, the car is not driving well. After a good 10 minutes, the power output is suddenly limited to 50kW, 70kW and sometimes 90kW. It makes it a very slow car, and dangerous when it happens while overtaking. No errors on the VDS (in debug mode), all temperatures are in the blue.

Did anyone ever experience something similar? I seems my local SeC has no clue again, and their only solution so far has been replacing motors, PEMs and battery packs. Preferably all together so they have more chance the problem has miraculously disappeared afterwards. It's not their money after all, so I suppose they don't really care.

 

[Marius]

Difficult for me to comment without further information.
In winter anyway when battery is hold at 5 degrees Celsius when outside is freezing, the power output is anyway limited around 75kW. Be sure you get the battery at operating temperature around 35 degrees Ceslius to reach the maximum power output. Mine has CAC of 102 so now in winter it does not reach more than 100kW. Only after a long drive 120km per hour on the motorway (30 minutes) you heat up the battery significantly to get maximum power. With older packs the maximum output anyway does not reach 200kW anymore since voltage decreases more than with a fresh pack hence output which is voltage multiplied with amperage does not reach maximum anymore.

 

[m0rph]

Outside temp: 5°C
Motor temp: 87°C
PEM temp: 28°C
Motor temp: 28°C

The problems only start after driving a good 10 minutes.

This is how it looks like from behind the steering wheel:

 

[spaceballs]

Outside temp: 5°C
Motor temp: 87°C
PEM temp: 28°C
Motor temp: 28°C

The problems only start after driving a good 10 minutes.

This is how it looks like from behind the steering wheel:

goto service menu: ESS: V&T: and see what min and max brick temperature is.

 

[m0rph]

goto service menu: ESS: V&T: and see what min and max brick temperature is.

Right after finishing standard charge:

Vmin 4.02V - Vmax 4.10V - Tmin: 14°C - Tmax: 15°C

After a night of balancing:

Vmin 4.01V - Vmax 4.05V - Tmin: 14°C - Tmax: 14°C

My car is always parked in a somewhat heated garage. Environment temps will never drop under 10°C.
The car behaved the same before and after balancing: power severely limited...

 

[spaceballs]

Right after finishing standard charge:

Vmin 4.02V - Vmax 4.10V - Tmin: 14°C - Tmax: 15°C

After a night of balancing:

Vmin 4.01V - Vmax 4.05V - Tmin: 14°C - Tmax: 14°C

My car is always parked in a somewhat heated garage. Environment temps will never drop under 10°C.
The car behaved the same before and after balancing: power severely limited...

I mean when your power limited. Also set alerts to debug mode.

 

[m0rph]

I mean when your power limited. Also set alerts to debug mode.

OK, it's already in debug mode. I'll have a test drive tonight and will check the Tmin and Tmax values at the moment the power is limited.

 

[petergrub]

Sounds like it could be a contact resistance problem where there are no temperature probes, since it takes a bit of driving to finally start seeing the effects. Check your log file for an abnormal current draw.

There are several current carrying cables that would have needed to be tightened all around the PEM. The three phase motor cables, ESS DC +/- cables, and the charge port cables. If your are comfortable around high voltage then check if they are tightened properly. The torques for each are:
Three phase motor cables: 9 Nm
ESS +: 9 Nm (Ground cable: 5 Nm)
ESS -: 5 Nm (Ground cable: 5 Nm)
Charge port cables: 5 Nm

Does the same thing happen when charging at 30-40 amps or more?

 

[m0rph]

Thanks, Peter.. I'm using "Tesla Graphical Log parser" but can't find current draw..
Charging looks fine (230V - 64A).

 

[petergrub]

I'm using "Tesla Graphical Log parser" but can't find current draw..

Check it out in scott451's log parser or VMSParser and look in the drive 1sec, 1min, and 10min records. You will find the ESS current and motor current in the 1 second drive records. spaceballs mentioned checking the brick temperatures; you will find those min/max temperatures for the bricks in the 1 minute drive records.

Charging looks fine (230V - 64A).

Good.

 

[Marius]

Your amperage shown in the screen does not match the power. At 50 kW power draw you should see around 130 A, but yours is around 70A. Same with regenerative. The shown amps are too low. I do not have any idea what this means......it might be contact resistance in your cables to the electric motor. If this is the case you should be careful since the heat built up will be enormous in the connectors.

 

[m0rph]

This is the data from the youtube video I posted above:

 

[m0rph]

Your amperage shown in the screen does not match the power. At 50 kW power draw you should see around 130 A, but yours is around 70A. Same with regenerative. The shown amps are too low. I do not have any idea what this means......it might be contact resistance in your cables to the electric motor. If this is the case you should be careful since the heat built up will be enormous in the connectors.

I noticed that too.. But I was not sure, as I always used that screen as a speedometer in the past.

 

[m0rph]

After some days of bad weather, I could finally go out and test again yesterday.
The power was limited after driving only 1 minute.
I checked the temps and had Tmin 9°C - Tmax 10°C.

 

[spaceballs]

After some days of bad weather, I could finally go out and test again yesterday.
The power was limited after driving only 1 minute.
I checked the temps and had Tmin 9°C - Tmax 10°C.

Temps seem fine.